Patterning of Mesenchyme - Secondary Mesenchyme

We can allow SMCs to touch the animal
pole region earlier than they would normally by denting down the animal
pole ectoderm. When this is done, in some cases the SMCs rapidly cease their
exploratory behavior an make stable attachments to the animal pole, resulting
in an abnormally short archenteron
(C). Go to the next page to see the converse experiment...